//
//  UIImage+Utilities.m
//  CBSystem
//
//  Created by Yuan Ryan on 12-7-30.
//  Copyright (c) 2012年 Yulong. All rights reserved.
//

#import "UIImage+Utilities.h"

@implementation UIImage (Utilities)

+ (CGSize)equalScaleSizeForMaxSize:(CGSize)maxSize actualSize:(CGSize)actualSize
{
    CGFloat picWidth = maxSize.width;
	CGFloat picHeight = maxSize.height;
    
    CGFloat actWidth = actualSize.width;
    CGFloat actHeight = actualSize.height;
	
	if(actualSize.width <= picWidth && actualSize.height <= picHeight)
	{
        actWidth = actualSize.width;
        actHeight = actualSize.height;
	}
	else if(actualSize.width > picWidth && actualSize.height <= picHeight)
	{
        actHeight = actHeight*picWidth/actWidth;
        actWidth = picWidth;
	}
	else if(actualSize.width <= picWidth && actualSize.height > picHeight)
	{
        actWidth = actWidth*picHeight/actHeight;
        actHeight = picHeight;
	}
	else if(actualSize.width > picWidth && actualSize.height > picHeight)
	{
		if((actualSize.width/picWidth) >= (actualSize.height/picHeight))
		{
            actHeight = picWidth/actWidth*actHeight;
            actWidth = picWidth;
		}
		else
		{
            actWidth = picHeight/actHeight*actWidth;
            actHeight = picHeight;
		}
	}
    CGSize euqalScaleSize = CGSizeMake(actWidth, actHeight);
    return euqalScaleSize;
}

- (UIImage *)fixOrientation {
    
    // No-op if the orientation is already correct
    if (self.imageOrientation == UIImageOrientationUp) return self;
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;
    
    switch (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
            
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
            
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationUpMirrored:
            break;
    }
    
    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationDown:
        case UIImageOrientationLeft:
        case UIImageOrientationRight:
            break;
    }
    
    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
                                             CGImageGetBitsPerComponent(self.CGImage), 0,
                                             CGImageGetColorSpace(self.CGImage),
                                             CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}

@end
